1. Field of the Invention
The present invention relates to an image forming apparatus, such as an electrophotographic copying machine and an electrophotographic printer.
2. Description of the Related Art
In an image forming apparatus using an electrophotographic system, such as a copying machine and a printer, a fan motor is widely used as a cooling unit of a power supply unit, a fixing unit and a processing unit that transfers an electrostatic latent image to a recording medium. In an image forming apparatus including a plurality of fan motors, the plurality of fans are driven at full-speed revolutions during operation of the image forming apparatus, during printing, and for a predetermined time after the end of printing. Therefore, there is a problem that operation sound caused by wind noise of the fans enters an audible range of the user.
The following configuration is proposed as a method of reducing the operation sound caused by the wind noise of the plurality of fan motors. More specifically, the fan motors are controlled such that other fan motors are stopped when some of the fan motors are in operation, and operation states of the fan motors are alternately switched at each predetermined period (for example, see Japanese Patent Application Laid-Open No. 2008-242488).
However, in the configuration with the plurality of fan motors, the operation sound caused by the wind noise of the fan motors may be heard more than the other operation sounds of the image forming apparatus. Therefore, a countermeasure for driving the fan motors according to the temperature state of the apparatus (for example, power supply apparatus) to be cooled by the fan motors to thereby reduce the noise caused by the wind noise of the fan motors in printing is desired. In a post-cooling state after the end of printing, the wind noise of the fan motors is heard more, and a countermeasure for reducing the operation sound caused by the fan motors is necessary.